xfs_scrub: in phase 3, use the opened file descriptor for repair calls

xfs_scrub: in phase 3, use the opened file descriptor for repair calls

While profiling the performance of xfs_scrub, I noticed that phase3 only
employs the scrub-by-handle interface for repairs.  The kernel has had
the ability to skip the untrusted iget lookup if the fd matches the
handle data since the beginning, and using it reduces the repair runtime
by 5% on the author's system.  Normally, we shouldn't be running that
many repairs or optimizations, but we did this for scrub, so we should
do the same for repair.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Eric Sandeen <sandeen@sandeen.net>